Critical Speed Damper

Abstract

It is shown that a damper applied to the spherical bearing at the ends of a rotating shaft to damp pitch and yaw motions of the journal bearing can markedly reduce the deflection caused by unbalance near critical speeds. Equations are given for optimizing the damping and for computing the damping moment which must be carried by the journal bearing. It is shown that with optimum damping of a centrally loaded uniform shaft, the load carried by the journal bearing in the critical-speed range is no more than 67 percent greater than it would have been for a rigid shaft. The corresponding moment carried by the journal bearing is less than the amount which would develop at the mid-length of the shaft in the absence of elastic deflections.